def test_get_size_of_cached_data():
test_obj = MPCache(1)
modified_time = time.time()
assert test_obj.get_size_of_cached_data() == 0
test_obj.refresh("some_key", "abcd", modified_time)
assert test_obj.get_size_of_cached_data() == sys.getsizeof("abcd")
test_obj.write("some_other_key", 42)
assert test_obj.get_size_of_cached_data() == sys.getsizeof(42)+sys.getsizeof("abcd")
test_obj.write("some_other_key", 52)
assert test_obj.get_size_of_cached_data() == sys.getsizeof(52)+sys.getsizeof("abcd")
test_obj.refresh("some_key", "abcd", modified_time)
assert test_obj.get_size_of_cached_data() == sys.getsizeof(52)+sys.getsizeof("abcd")
